Doug Hamilton hiked all the way to the northern most tip of the island and south past a fish camp where some panga fishermen were also waiting out the wind. A few of the fishermen came by hiking to visit during the day. Andrea Wolf talked them out of a fish to add to our dinner. They would have given it to us free but Doug went by their camp later and gave them $5 US for it. It was my turn to cook a meal so I filleted the fish and made Thai Green Curry Fish for dinner.
Following the advice we received from John Weed when we met him on Isla Angel de la Guardia, Doug Hamilton and I had each bought ourselves a hand-pumped desalinator. We did not need them for this trip but figured it would be good practice to try them out now instead of waiting until we were dependant on them. I started with 10 liters of water in reserve in one MSR Dromedary bag. Then once a day or so I made a few liters of fresh water. On this day when we were winded in on Isla San Marcos the water was so rough and turbid that we didn't want to drop our desalinator intakes into it. This is bothersome, on the days when you might need fresh water the most, on the days when you have nothing better to do, you cannot use the desalinator! Perhaps if we had been blown in for a week and become desperate we would have found a way to get it to work. Other than that day the desalinators worked well and produced all the water we needed in only 45 minutes or so a day.
I took a cap from an old wine bag, poked a hole in it with my pocket knife and inserted the outlet hose from my desalinator through it. Instant low-cost fitted tubing system to desalinate directly into a wine bag. I preferred to make fresh water into this and transfer it to my dromedary bag later. Actually, I preferred making it directly into my Nalgene water bottle because it fills up in only 15 minutes or less and you can see how much progress you are making. I considered buying a replacement Nalgene bottle cap at REI, since these fit on dromedary bags. Drill a hole in one to make a cheap fill cap. Doug found that the hose from his cammelback fit on the outlet nipple from the desalinator and pumped water directly into his hydration bag.
There were a lot of jokes about the guys sitting around jerking off with their desalinators. I sat on a folding stool on the rocks while pumping, which made Kate DesLauriers say I looked like I was "practicing my cello". We also joked about printing up an exercise book titled "Biceps and Triceps of Steel in only 20 gallons. A guide to exercising with your Survivor 35". We could photograph someone with good muscle definition (how about Gregg Berman?) pumping fresh water in several different positions and have Mary Ann Furda tell us which muscle groups to paint red in the pictures and what their names are.
The manual says to pump the arm once every two seconds. This is necessary when priming the desalinator because if you pump too fast the bypass valve opens up and it never develops pressure. But Doug discovered that after the pressure is up and all the air is out of the system, you can pump twice as fast without the bypass going off. I did a test one morning: I pumped one liter at the recommended 2 seconds per stroke and it took 18 minutes. Then I made a second liter pumping at 1 second per stroke and it took 11 minutes. Not twice as much in the same amount of time but probably worth the extra effort.
On the down stroke you can use one hand on the lever with resistance from you legs under the housing. But on the upstroke you have to hold the housing down with your other hand. There is strong initial resistance, a jerk to the housing-hand that is unpleasant. I used a Velcro strap to attach the housing to my leg and found it much easier to pump with just one hand. I can switch hands back and forth or even pump with both hands on the lever. More positions for different muscle groups for the exercise book.
Doug had a problem with his desalinator: The intake hose was kinked from being folded in storage. On the intake stroke, the hose would collapse at the kink and not get enough water. His desalinator made a lot less water per hour than it should when this happened. Eventually he solved the problem by putting a piece of spiral strain-relief material on the hose that forced it to stay round. Mine has a small kink there that isn't bad enough (yet) to collapse. It is something to keep an eye on. But in the end the desalinators worked as advertized and made enough water fast enough that I am ready to trust one to keep me alive on an upcomming trip where I will not be able to buy water.